Catalytic reaction apparatus have been commonly used in industry to produce industrial gases such as a hydrogen enriched fuel gas and are therefore well known in the art. The most common approach for producing hydrogen is the steam reforming process in which a raw fuel gas is mixed with steam and passed through catalyst beds disposed in a tubular reformer. Heat for this endothermic reaction is provided from a furnace in which the tubes are locoted in a widely spaced apart configuration.
As a result of the large size and limited operating flexibility characteristics of these industrial units, steam reforming technology was not successfully integrated for use with power plants that incorporated hydrogen consuming fuel cells until the successful application as disclosed in U.S. Pat. Nos. 4,098,587; 4,098,588 and 4,098,589. The new design represented by these patents consisted of a compact reaction apparatus with a number of important features that made it suitable for use within a fuel cell power plant.
Namely, it is a compact reaction apparatus for steam reforming a raw fuel that is mainly characterized by having: a plurality of vertical tubular reformers closely packed (by the then standard of the art) within a furnace and shielded so as to produce an evenly heated tube at any location within the array of tubes; having a burner cavity area and an enhanced heat transfer area; and having annular reformers incorporating regenerative heat transfer capability between the reaction products and the process stream.
This design resulted in a steam reformer apparatus that met the size and operating characteristic requirements of a fuel cell power plant while maintaining a high thermal efficiency that is necessary to ensure a competitive overall power plant operating efficiency.
While the design disclosed in the aforesaid patents was a milestone achievement for the application of hydrogen generation technology to fuel cell power plants, these early designs were in need of improvements to make it truly more compact, lighter in weight, more uniform in its heat distribution and catalyst bed stability. Chief among these problems is the need to develop an efficient supporting structure that keeps the tube bundle aligned and properly distributes the loading forces resulting from tubes and catalyst and ancillary equipment without undue weight penalty or complex and costly structural fixtures.